The Lindsay Centennial Symposium and Public Lecture Friday 26th January 2007 Rotunda Theatre, St. Patrick's Trian, Armagh. The Lindsay Centennial Symposium is a one-day conference to celebrate the 100th anniversary of the birth of the former director of the Armagh Observatory, Dr Eric Mervyn Lindsay. The meeting will take place in the Rotunda Theatre, St. Patrick's Trian, Armagh, from approximately 09:30 to 17:30, and will be followed by an evening Public Lecture "Robert Ball: Ireland's Astronomical Muse", by Dr Allan Chapman (University of Oxford). The lecture will begin at 20:00 and finish with light refreshments at approximately 21:30. Dr Eric Mervyn Lindsay was one of the most influential Irish astronomers of the twentieth century, director of the Armagh Observatory from 1937 until his death in 1974. Amongst many achievements he is perhaps best remembered for founding the Armagh-Dunsink-Harvard (ADH) Telescope at the Boyden Observatory in Bloemfontein, South Africa, in 1950; establishing the Armagh Planetarium in 1968; and recruiting Dr Ernst J. Opik, one of the foremost theoretical astronomers of his generation. The Harvard Boyden Station in South Africa became the first international astronomical observatory, arguably the forerunner of the European Southern Observatory in Chile. Similarly, the 1947 agreement setting up the ADH Telescope is believed to be the first example of "North-South" collaboration between the two jurisdictions on the island of Ireland. The Armagh Observatory maintains many international collaborations and continues its South African connections through participation in the Southern African Large Telescope (SALT) project. The Armagh Planetarium, which has recently reopened following refurbishment, is the largest and most successful astronomy education facility on the island of Ireland. Ernst Opik became famous not just for the breadth of his astronomical knowledge and establishing the academic credentials of the Armagh Observatory during the mid-twentieth century but also for providing a theoretical basis for understanding the Near-Earth Object impact hazard to life on Earth. The Lindsay Symposium will provide a forum to promote modern astronomical research throughout the island of Ireland. The morning will be devoted to a largely historical review of Lindsay's principal contributions to Irish Astronomy, beginning with an invited talk by the noted Irish astronomer, author and historian, Dr Maire Bruck (University of Edinburgh) entitled "Armagh, Dunsink and the Early Days of the Irish Astronomical Society". Later talks in the morning, by Dr John Butler (Armagh Observatory) and Dr Tom Mason (Armagh Planetarium), will review the Armagh-Dunsink-Harvard telescope and Lindsay's role in establishing the Armagh Planetarium. The morning session will conclude with talks by James O'Connor (Irish Astronomical Society) and Terry Moseley (Irish Astronomical Association), who will provide a personal perspective of Lindsay and his period in office. Afternoon talks will focus on modern astronomical research, with contributions from (among others) Professor Tom Ray (Dublin Institute for Advanced Studies), Dr Andy Shearer (NUI Galway), and Dr Brian Espey (Trinity College Dublin). The Centennial Symposium will close with a personal contribution by a member of the Lindsay family, Mr Robin Lindsay. The day's activities will conclude with an evening public lecture by Dr Allan Chapman (University of Oxford), entitled "Robert Ball: Ireland's Astronomical Muse". Allan Chapman is a world-famous historian of science and an exceptionally good public speaker. A copy of the current programme and related information about the meeting is available from the Observatory web-site, at http://star.arm.ac.uk/lindsay/. Other information, as well as a short biography of Dr Lindsay, written a few years ago by the Observatory Librarian, Mr John McFarland, can be obtained from http://star.arm.ac.uk/history/lindsay.html or as links therein. Tickets for the event, either the one-day conference or the evening public lecture (or both), are free on application to Mrs Aileen McKee, Armagh Observatory, College Hill, Armagh BT61 9DG; Tel: 028-3752-2928; Fax: 028-3752-7174; e-mail: ambn@arm.ac.uk. As numbers in the Rotunda Theatre are limited, we would be grateful if those wishing to attend the conference and/or the evening public lecture would please return the enclosed pro-forma as soon as possible, or contact Mrs Aileen McKee by telephone or e-mail, to confirm their participation and to assist with our preparations for the meeting.